Percentage of documented cases of transmission through oral sex?

Aug 15, 1996

Due to the ambiguity concerning the risk factors of oral sex among gay men, I wondered if you had any hard-core data on the number of documented cases in which oral sex was the only possible mode of transmission? Is there a significant decrease in risk of transmission for those who practice oral sex without a condom, but do not allow his partner to ejaculate in his mouth? Secondly, what does this data suggest in terms of defining this type of behavior as "low" or "high" risk? I ask this question because I had read elsewhere on the Internet that most new cases of HIV transmission today is due to unprotected, receptive (as opposed to insertive) anal intercourse. Is this true? Thanks for responding.

Response from Mr. Sowadsky

Hi. Thank you for posting your questions. I'll answer them one at a time.

"Due to the ambiguity concerning the risk factors of oral sex among gay men,
I wondered if you had any hard-core data on the number of documented cases
in which oral sex was the only possible mode of transmission?"

We do not keep statistics on the number of people who became infected through
oral sex, nor do we keep statistics on the number of people who became
infected by vaginal intercourse, anal intercourse, etc. We also do not keep
statistics on the number of people who became infected by receptive
intercourse as compared to insertive intercourse.

Statistics however are kept on whether a persons sexual partners are male
and/or female, their IV drug use history, blood transfusion history etc. But
we don't keep statistics on the specific sexual activity that a person became
infected by.

The data that we do have on oral sex transmission comes from clinical case
reports in the medical literature. There have been several case reports
documenting oral sex transmission of HIV. All of these cases were in people
giving oral sex (exposure to semen etc.). There have not been any cases of
HIV transmission through receiving oral sex (exposure to saliva).

There was also a study looking at SIV (the monkey AIDS virus) to see if oral
sex transmission was possible. SIV is transmitted the same way as HIV, and
is very similar genetically to HIV. This study showed that SIV/HIV
transmission is possible if these viruses were to get into the mouth/throat,
and backs up clinical case reports. This study did not however quantify the
risks.

In regard to the risks of giving oral sex, all we can say is that the risk is
less than that of intercourse, but the risk is there, and transmission has
occurred this way. We can also say that there have been cases of HIV
transmission through giving oral sex, but no statistics are collected as to
just how many people became infected specifically this way.

"Is there a significant decrease in risk of transmission for those who
practice oral sex without a condom, but do not allow his partner to ejaculate
in his mouth?"

If you were to give a man oral sex, and don't allow him to ejaculate in your
mouth, the risk of oral sex transmission would decrease significantly (but
not be eliminated). The more infectious body fluid you get in your mouth,
the greater the chance of transmission. If you're only exposed to pre-cum,
there is a chance of transmission, but normally a person is only exposed to a
small quantity of pre-cum. If the man ejaculates, you're exposed to a much
greater quantity of semen as compared to pre-cum. So without ejaculation,
there would be a risk of transmission, but not a great risk. With
ejaculation, the risk would go up substantially.

"Secondly, what does this data suggest in terms of defining this type of
behavior as "low" or "high" risk? I ask this question because I had read
elsewhere on the Internet that most new cases of HIV transmission today is
due to unprotected, receptive (as opposed to insertive) anal intercourse. Is
this true?"

As to what defines high risk vs. low risk is a relative term. For example,
the receptive partner during anal/vaginal sex is at higher risk of infection
than the insertive partner, but BOTH partners are at significant risk of
infection if the other partner is already infected with this or other
Sexually Transmitted Diseases (STD's).

There is a myth out there that the insertive partner during anal sex (the
"top") is at low risk of infection. This is incorrect. The insertive
partner is at high risk during anal sex, and the receptive partner (the
"bottom") is at even higher risk. Neither partner is at low risk. And as I
stated earlier, we do not keep statistics on the number of people who became
infected by receptive intercourse as compared to insertive intercourse.

So in summary, anal sex is risky for both partners, but especially the
receptive partner. Oral sex is risky for the giving partner, but not as
risky as anal sex. If a person ejaculates in your mouth, your risk of
infection increases significantly. And finally, nobody has ever been
infected by receiving oral sex.

If you have further questions, please e-mail me at "nvhotline@aol.com" or call me at 1-800-842-AIDS.

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